Currently, the sliver produced on sliver producing textile machines is deposited especially in cylindrical containers fitted with a movable bottom actuated by a pressure spring situated under the bottom and lifting the bottom of the container, when the latter is empty, almost to the upper edge of the container and compressed by the bottom downwards as the sliver is gradually deposited on the movable bottom of the container. When the containers are full, i.e., filled with the sliver, they are moved to a sliver processing machine such as an open-end spinning machine where the sliver is gradually taken from the container and the bottom correspondingly moves upwards due to the decreasing weight of the sliver amount deposited in and gradually leaving the container. Due to this, the sliver is at all times taken from the upper section of the inner space of the container, and the sliver end, due to a possible sliver interruption, is accessible to the operator.
The drawback of these cylindrical containers consists in their limited capacity determined by the maximum diameter allowing to place them under the operating units of the sliver processing machines. To achieve the maximum capacity, the cylindrical containers must be arranged partly one behind the other in order to permit their diameter to be equal to almost the double of the spacing between the operating units of the machine. Such arrangement of the cylindrical containers is a serious impediment to the possibility of replacing automatically an emptied container by a full one, the replacement of the rear container requiring the handling of two containers. Consequently, the attempts to automize this process have failed, and said exchange of the cylindrical containers is carried out manually. However, even the manual exchange requires the operator to handle at least one additional container.
Especially for these reasons, more advantageous are flat sliver containers whose width corresponds to the width of one operating unit of a spinning machine minus a necessary handling gap, and the width, at least to the width of the machine space under the operating units. Such flat containers have been coming into use in particular in the rotor spinning machines with automatic container exchange but due to their advantages are likely to replace the cylindrical sliver containers in other types of spinning machines as well.
From the point of view of the motion and construction of the bottom of the flat container of the textile fibre sliver, the currently used flat containers can be divided into two groups. To the first group belong flat containers whose bottom, like that of the cylindrical containers, is seated on compressible spiral sprins. To prevent the movable bottom of the flat container from sinking unevenly on the mutually opposed bottom edges in its longitudinal direction, a well-known lever mechanism, disclosed for instance in EP 344 484, can be situated between said spiral springs. In the crossing points of the lever mechanisms there are horizontally and at the respective crossing point rotatably mounted reinforcing members whose ends are connected by means of a joint with the respective opposed spiral spring.
This arrangement of the flat container involves problems during the feeding of a fully loaded container. The sliver is deposited into the container under pressure and therefore comes to reach over the upper edge of the flat container with the risk for the upper layers of the sliver to fall down or to get caught during the feeding, and for the sliver, to get damaged or interrupted. The upper layer has limited stability in the direction normal to the longitudinal axis plane of the flat container which is in most cases the direction the flat containers move in while being fed. The material reaching over the upper edge of the container is source of troubles while the sliver is being taken out of the container under a spinning machine, and this problem requires solution for instance by increasing the height of the machine or by reducing the height of the container. In this flat container, the pressure exerted on the sliver while being deposited into the container can be neither changed nor regulated.
In the second group of flat containers, disclosed for instance in the patent CZ 280616, the bottom adapted freely to move vertically consists of a plate. Before the start of the sliver filling process, a lifting device moves the bottom towards the upper edge of the flat container; then, during the filling process, the bottom sinks as far as to the lower edge of the container reached when the flat container is completely full.
The drawback of this solution consists in particular in the fact that the bottom of the flat container constantly remains in its lower position while the sliver is being taken off under a spinning machine. The relation between the height and width of the flat container renders it very difficult for the machine operator to find in, and to pick out from, the flat container the sliver end, if the sliver interruption occurs with the flat container less than half-filled.